The present invention relates to a magnetoresistive element with a thin ferromagnetic film, and a magnetic sensor or magnetic head to which the magnetoresistive element is applied.
In rectangular magnetoresistive elements, an ideal magnetic domain structure comprises gyrate magnetic domains. However, in practice, pattern edges may not be linearized due to overetching; and a modified layer due to a finishing process is formed as a surface layer which contacts a magnetic medium when the magnetoresistive element is used as a magnetic head. Thus, the domain structure becomes deteriorated. The disturbance of the domains causes abrupt domain wall transition and irregular magnetization when an external field is applied. Split and Barkhausen noise occur in a change in electric resistance, that is, in an output. Further, secondary harmonic distortion is increased in the playback waveform. Thus, the magnetoresistive element can hardly be used for commercial applications.